Keep Birds Aloft on Their Spring Journey

By the time you read this, songbird migration will be at its peak throughout gloriously temperamental springtime Oregon! Fully eighty percent of our terrestrial migrants in North America migrate at night, including warblers, thrushes, sparrows, kinglets, siskins, and grosbeaks. Migrating at night provides a number of benefits: birds can avoid daytime predators, preserve daylight hours for foraging, take advantage of a less turbulent atmosphere, and use the stars to navigate!

Unfortunately, this tactic also exposes them to an increasingly widespread threat— artificial light that is cast into the night sky all night long from unshielded and overly bright fixtures on our homes, streets, buildings, billboards, and empty parking lots. All of these sources accumulate to produce “sky glow”— the hazy dome of light over our cities and developed landscapes—which mars our view of the heavens and washes out the birds’ star map.

CSU’s AeroEco Lab for Oregon the night of May 5, 2021

You may remember the story of 398 songbirds colliding with the 23-story Standard Insurance building in Galveston, Texas, in May of 2017. Or the 310 Chimney Swifts that hit the low-rise NASCAR Hall of Fame in Charlotte, North Carolina, in October of 2019. These catastrophic collision events capture nationwide attention and heighten awareness of the hazard that light at night poses for migratory birds, but there are countless more common cases of birds being drawn off their nocturnal migration journeys that go largely unnoticed.

Thankfully, there are tools to help us reduce light pollution during peak migration season. Though songbird migration spans three months in both spring and fall, most of the birds that fly over Oregon will do so during a one-month period each season, from mid-April to mid-May and again between mid-September and mid-October. Researchers at Colorado State University’s AeroEco Laboratory are using radar technology to track movements of birds on migration, and then posting unequivocal alerts about peak movement nights on their website ( Red, orange, and yellow alerts signal large movements of birds, with red alerts representing the highest forecasts relative to total peak historic bird migration. There are generally fewer than ten red alert nights per season, and we encourage people to turn off all unnecessary outdoor lights at least on these peak movement nights, if not for the entire peak month in spring and fall!

Night Sky over Alvord Desert by Michael Montgomery

Bear in mind, light pollution doesn’t just impact migrating birds. It impacts entire ecosystems, including both migrating and nesting birds, fish, mammals, amphibians, invertebrates, and plants as well as human health, safety, and culture. Bird Alliance of Oregon is working to raise awareness about the importance of the night sky as a natural resource that is slipping away, little by little.

Help save our night skies:

  • Watch for our Lights Out Alerts on social media this May and turn off your unnecessary lighting
  • Check out CSU’s AeroEco Lab for alerts in various cities and statewide
  • Take the Pledge to Go Lights Out:
  • Turn lights off when you’re not using them
  • Make sure that all your lights are shielded and aimed down
  • Switch to motion sensors (or motion sensor bulbs)
  • Use bulbs only as bright as you need
  • Choose warm bulbs (yellower > whiter)
  • Close blinds/shades at night during migration seasons
  • Help advocate for good lighting standards in your city

For more information, contact Mary Coolidge at